In related art, a game system is known which includes a game apparatus, a controller for operating the game apparatus and a display apparatus (for example, refer to PTL 1).
In the game system disclosed in PTL 1, an operation signal in accordance with an operation of a player is transmitted from the controller to the game apparatus, and the game apparatus executes a game program in accordance with the received operation signal to advance the game. Further, the game apparatus transmits a game screen image indicative of a progress situation of the game being advanced to the display apparatus such that the game screen image is displayed on the display apparatus.
It is to be noted that the controller has operation devices called analog stick at left and right positions thereof. The analog sticks have a joystick structure having two axes orthogonal to each other and have an operation member provided for tilting motion with respect to a housing of the controller. The controller outputs an operation signal including a coordinate value of the operation member in accordance with a direction of the tilting operation.
Meanwhile, some game apparatuses in recent years are configured such that not only a controller having direction keys, operation buttons and so forth disclosed in PTL 1 described hereinabove, but also a pointing device such as a so-called mouse can be connected thereto. Also it is possible for the game apparatus to advance a game in response to an operation signal received from the pointing device connected thereto.
Further, in the game system disclosed in PTL 1, a direction key which allows upward, downward, leftward and rightward inputs and a plurality of buttons are disposed on the controller, and an operation signal in accordance with an input of any of the key and buttons is outputted. Further, the game apparatus is a so-called installation type game apparatus and advances, if the operation signal is received from the controller, a game in accordance with the received operation signal.
Further, a portable terminal is known wherein a controller and a display apparatus are integrated with each other and a processing apparatus provided in a housing advances a game in accordance with an operation signal inputted from the controller (for example, refer to PTL 2).
Incidentally, in a game executed in an information processing device such as the game apparatus or a portable terminal described above, a key assignment is set in advance. The key assignment is to assign a function to each key or each button, and, for example, if the controller outputs an operation signal in response to an input of a certain button, then the game apparatus specifies the inputted button on the basis of the operation signal and thereby recognizes that the button is inputted.